Hello Chaps,
I did not do my instructor course before my instrument rating, however, I did do an IR renewal after 18 months of instructing. I know it is not quite the same, but one thing you will find when you move onto the IR course you will have alot more capacity, due to the fact you have been subjected to the 'flying' environment. You will also have developed your flying skills and spacial awareness.
To answer your second question, I don't think you will have a problem finding a job if you do the course over seas, at the end of the day you will have the ticket in your licence. Another thing to consider is that the demand for instructors at the moment is quite high, so finding a job will most likely be fairly easy.
Instructing is a very rewarding job, and also will provide you with alot of enjoyment.
All the best with it, and enjoy it.
Cheers.